Valorization of co-products of sardine waste by physical treatment under natural and forced convection solar drying

Abstract

This work aims to valorise a co-product resulting from the sardine processing chain (Sardina pilchardus) in order to obtain the compounds of interest by the implementation of soft techniques seeking a wider investment, low energy cost and low environmental pollution impacts caused by conventional systems, which are valid also for other co-products of fresh sardine waste. For this purpose, a thermo-kinetic study was carried out in a natural and forced convection solar drying in order to establish the optimal conditions for drying and storing sardine heads, which are an important source of high quality proteins for human and animal nutrition. Static gravimetric method was used to determine the optimal water activity for conservation of sardine heads. Kinetics of drying is studied for three temperatures 60, 70 and 90 °C, in a two air–flow drying 150 m3 h−1and 300 m3 h−1. The air drying temperature is the most important factor influencing the drying kinetics of sardine heads. Total energy consumption showed a downward trend with increasing temperature and an upward trend with increasing air flow. The exergy loss, exergy transfer rate from evaporation and exergy efficiency of the drying chamber were investigated in this study.